Architect and engineer; in 1458 the initial project for Palazzo Pitti was commissioned of him in Florence. He also collaborated with Alberti in Mantua for the Gonzaga dukes, while in 1487 he was in Milan, where he met Leonardo.
Fancelli had been summoned to that city to judge the projects for the lantern over the Milan Cathedral, on which Leonardo too was working. And it was from Milan that Fancelli wrote on August 12, 1487, in agreement with the ambassador of Florence Pietro Alamanni, to Lorenzo the Magnificent, describing a project destined to make the Arno navigable from Florence (Mulina d’Ognissanti) to Signa, following the natural course of the river. From the words of Vasari and the descriptions of Fancelli it can be seen that this was not a question of creating an alternative course for the river, but rather of «putting it in a canal». Fancelli's daughter Chiara married Perugino.